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package jsr166y; |
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import java.util.concurrent.*; |
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import java.util.concurrent.atomic.*; |
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import java.util.concurrent.atomic.AtomicReference; |
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import java.util.concurrent.locks.LockSupport; |
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import sun.misc.Unsafe; |
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import java.lang.reflect.*; |
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/** |
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* A reusable synchronization barrier, similar in functionality to a |
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* |
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* <ul> |
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* |
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* <li> The number of parties synchronizing on a phaser may vary over |
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* time. A task may register to be a party at any time, and may |
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* deregister upon arriving at the barrier. As is the case with most |
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* basic synchronization constructs, registration and deregistration |
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* affect only internal counts; they do not establish any further |
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* internal bookkeeping, so tasks cannot query whether they are |
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* <li> The number of parties <em>registered</em> to synchronize on a |
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* phaser may vary over time. Tasks may be registered at any time |
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* (using methods {@link #register}, {@link #bulkRegister}, or forms |
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* of constructors establishing initial numbers of parties), and may |
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* optionally be deregistered upon any arrival (using {@link |
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* #arriveAndDeregister}). As is the case with most basic |
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* synchronization constructs, registration and deregistration affect |
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* only internal counts; they do not establish any further internal |
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* bookkeeping, so tasks cannot query whether they are |
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* registered. (However, you can introduce such bookkeeping by |
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* subclassing this class.) |
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* |
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* <li> Each generation has an associated phase value, starting at |
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* zero, and advancing when all parties reach the barrier (wrapping |
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* around to zero after reaching {@code Integer.MAX_VALUE}). |
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* |
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* <li> Like a CyclicBarrier, a Phaser may be repeatedly awaited. |
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* Method {@code arriveAndAwaitAdvance} has effect analogous to |
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* {@code CyclicBarrier.await}. However, Phasers separate two |
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* aspects of coordination, that may also be invoked independently: |
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* <li> Each generation has an associated phase number. The phase |
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* number starts at zero, amd advances when all parties arrive at the |
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* barrier, wrapping around to zero after reaching {@code |
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* Integer.MAX_VALUE}. |
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* |
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* <li> Like a {@code CyclicBarrier}, a phaser may be repeatedly |
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* awaited. Method {@link #arriveAndAwaitAdvance} has effect |
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* analogous to {@link java.util.concurrent.CyclicBarrier#await |
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* CyclicBarrier.await}. However, phasers separate two aspects of |
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* coordination, which may also be invoked independently: |
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* |
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* <ul> |
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* |
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* <li> Arriving at a barrier. Methods {@code arrive} and |
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* {@code arriveAndDeregister} do not block, but return |
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* the phase value current upon entry to the method. |
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* |
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* <li> Awaiting others. Method {@code awaitAdvance} requires an |
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* argument indicating the entry phase, and returns when the |
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* barrier advances to a new phase. |
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* <li> Arriving at a barrier. Methods {@link #arrive} and |
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* {@link #arriveAndDeregister} do not block, but return |
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* an associated <em>arrival phase number</em>; |
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* that is, the phase number of the barrier to which the |
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* arrival applied. |
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* |
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* <li> Awaiting others. Method {@link #awaitAdvance} requires an |
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* argument indicating an arrival phase number, and returns |
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* when the barrier advances to a new phase. |
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* </ul> |
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* |
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* |
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* <li> Barrier actions, performed by the task triggering a phase |
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* advance while others may be waiting, are arranged by overriding |
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* method {@code onAdvance}, that also controls termination. |
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* Overriding this method may be used to similar but more flexible |
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* effect as providing a barrier action to a CyclicBarrier. |
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* advance, are arranged by overriding method {@link #onAdvance(int, |
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* int)}, which also controls termination. Overriding this method is |
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* similar to, but more flexible than, providing a barrier action to a |
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* {@code CyclicBarrier}. |
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* |
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* <li> Phasers may enter a <em>termination</em> state in which all |
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* actions immediately return without updating phaser state or waiting |
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* for advance, and indicating (via a negative phase value) that |
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* execution is complete. Termination is triggered by executing the |
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* overridable {@code onAdvance} method that is invoked each time the |
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* barrier is about to be tripped. When a Phaser is controlling an |
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* action with a fixed number of iterations, it is often convenient to |
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* override this method to cause termination when the current phase |
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* number reaches a threshold. Method {@code forceTermination} is also |
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* available to abruptly release waiting threads and allow them to |
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* terminate. |
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* execution is complete. Termination is triggered when an invocation |
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* of {@code onAdvance} returns {@code true}. When a phaser is |
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* controlling an action with a fixed number of iterations, it is |
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* often convenient to override this method to cause termination when |
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* the current phase number reaches a threshold. Method {@link |
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* #forceTermination} is also available to abruptly release waiting |
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* threads and allow them to terminate. |
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* |
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* <li> Phasers may be tiered to reduce contention. Phasers with large |
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* numbers of parties that would otherwise experience heavy |
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* |
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* <li> By default, {@code awaitAdvance} continues to wait even if |
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* the waiting thread is interrupted. And unlike the case in |
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* CyclicBarriers, exceptions encountered while tasks wait |
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* {@code CyclicBarrier}, exceptions encountered while tasks wait |
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* interruptibly or with timeout do not change the state of the |
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* barrier. If necessary, you can perform any associated recovery |
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* within handlers of those exceptions, often after invoking |
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* {@code forceTermination}. |
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* |
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* <li>Phasers ensure lack of starvation when used by ForkJoinTasks. |
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* <li>Phasers may be used to coordinate tasks executing in a {@link |
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* ForkJoinPool}, which will ensure sufficient parallelism to execute |
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* tasks when others are blocked waiting for a phase to advance. |
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* |
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* <li>The current state of a phaser may be monitored. At any given |
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* moment there are {@link #getRegisteredParties}, where {@link |
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* #getArrivedParties} have arrived at the current phase ({@link |
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* #getPhase}). When the remaining {@link #getUnarrivedParties}) |
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* arrive, the phase advances. Method {@link #toString} returns |
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* snapshots of these state queries in a form convenient for |
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* informal monitoring. |
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* |
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* </ul> |
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* |
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* <p><b>Sample usages:</b> |
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* |
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* <p>A Phaser may be used instead of a {@code CountDownLatch} to control |
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* a one-shot action serving a variable number of parties. The typical |
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* idiom is for the method setting this up to first register, then |
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* start the actions, then deregister, as in: |
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* <p>A {@code Phaser} may be used instead of a {@code CountDownLatch} |
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* to control a one-shot action serving a variable number of |
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* parties. The typical idiom is for the method setting this up to |
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* first register, then start the actions, then deregister, as in: |
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* |
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* <pre> {@code |
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* void runTasks(List<Runnable> list) { |
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* void runTasks(List<Runnable> tasks) { |
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* final Phaser phaser = new Phaser(1); // "1" to register self |
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* for (Runnable r : list) { |
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* // create and start threads |
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* for (Runnable task : tasks) { |
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* phaser.register(); |
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* new Thread() { |
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* public void run() { |
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* phaser.arriveAndAwaitAdvance(); // await all creation |
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* r.run(); |
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* phaser.arriveAndDeregister(); // signal completion |
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* task.run(); |
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* } |
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* }.start(); |
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* } |
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* |
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* doSomethingOnBehalfOfWorkers(); |
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* phaser.arrive(); // allow threads to start |
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* int p = phaser.arriveAndDeregister(); // deregister self ... |
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* p = phaser.awaitAdvance(p); // ... and await arrival |
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* otherActions(); // do other things while tasks execute |
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* phaser.awaitAdvance(p); // await final completion |
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* // allow threads to start and deregister self |
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* phaser.arriveAndDeregister(); |
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* }}</pre> |
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* |
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* <p>One way to cause a set of threads to repeatedly perform actions |
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* for a given number of iterations is to override {@code onAdvance}: |
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* |
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* <pre> {@code |
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* void startTasks(List<Runnable> list, final int iterations) { |
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* void startTasks(List<Runnable> tasks, final int iterations) { |
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* final Phaser phaser = new Phaser() { |
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* public boolean onAdvance(int phase, int registeredParties) { |
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* return phase >= iterations || registeredParties == 0; |
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* } |
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* }; |
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* phaser.register(); |
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* for (Runnable r : list) { |
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* for (Runnable task : tasks) { |
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* phaser.register(); |
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* new Thread() { |
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* public void run() { |
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* do { |
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* r.run(); |
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* task.run(); |
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* phaser.arriveAndAwaitAdvance(); |
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* } while(!phaser.isTerminated(); |
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* } |
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* phaser.arriveAndDeregister(); // deregister self, don't wait |
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* }}</pre> |
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* |
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* <p> To create a set of tasks using a tree of Phasers, |
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* <p>To create a set of tasks using a tree of phasers, |
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* you could use code of the following form, assuming a |
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* Task class with a constructor accepting a Phaser that |
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* Task class with a constructor accepting a phaser that |
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* it registers for upon construction: |
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* <pre> {@code |
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* void build(Task[] actions, int lo, int hi, Phaser b) { |
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* |
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* <p><b>Implementation notes</b>: This implementation restricts the |
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* maximum number of parties to 65535. Attempts to register additional |
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* parties result in IllegalStateExceptions. However, you can and |
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* parties result in {@code IllegalStateException}. However, you can and |
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* should create tiered phasers to accommodate arbitrarily large sets |
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* of participants. |
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* |
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private static final int phaseMask = 0x7fffffff; |
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private static int unarrivedOf(long s) { |
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return (int)(s & ushortMask); |
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return (int) (s & ushortMask); |
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} |
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private static int partiesOf(long s) { |
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return ((int)s) >>> 16; |
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return ((int) s) >>> 16; |
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} |
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private static int phaseOf(long s) { |
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return (int)(s >>> 32); |
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return (int) (s >>> 32); |
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} |
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private static int arrivedOf(long s) { |
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} |
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private static long stateFor(int phase, int parties, int unarrived) { |
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return ((((long)phase) << 32) | (((long)parties) << 16) | |
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(long)unarrived); |
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> |
return ((((long) phase) << 32) | (((long) parties) << 16) | |
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(long) unarrived); |
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} |
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private static long trippedStateFor(int phase, int parties) { |
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long lp = (long)parties; |
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return (((long)phase) << 32) | (lp << 16) | lp; |
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long lp = (long) parties; |
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> |
return (((long) phase) << 32) | (lp << 16) | lp; |
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} |
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|
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/** |
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private final Phaser parent; |
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|
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/** |
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* The root of Phaser tree. Equals this if not in a tree. Used to |
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* The root of phaser tree. Equals this if not in a tree. Used to |
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* support faster state push-down. |
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*/ |
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private final Phaser root; |
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private final AtomicReference<QNode> oddQ = new AtomicReference<QNode>(); |
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|
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private AtomicReference<QNode> queueFor(int phase) { |
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return (phase & 1) == 0? evenQ : oddQ; |
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> |
return ((phase & 1) == 0) ? evenQ : oddQ; |
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} |
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/** |
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* root if necessary. |
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*/ |
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private long getReconciledState() { |
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return parent == null? state : reconcileState(); |
287 |
> |
return (parent == null) ? state : reconcileState(); |
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} |
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/** |
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} |
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|
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/** |
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* Creates a new Phaser without any initially registered parties, |
314 |
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* Creates a new phaser without any initially registered parties, |
315 |
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* initial phase number 0, and no parent. Any thread using this |
316 |
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* Phaser will need to first register for it. |
316 |
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* phaser will need to first register for it. |
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*/ |
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public Phaser() { |
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this(null); |
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} |
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|
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/** |
323 |
< |
* Creates a new Phaser with the given numbers of registered |
323 |
> |
* Creates a new phaser with the given numbers of registered |
324 |
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* unarrived parties, initial phase number 0, and no parent. |
325 |
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* |
326 |
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* @param parties the number of parties required to trip barrier |
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} |
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|
334 |
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/** |
335 |
< |
* Creates a new Phaser with the given parent, without any |
335 |
> |
* Creates a new phaser with the given parent, without any |
336 |
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* initially registered parties. If parent is non-null this phaser |
337 |
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* is registered with the parent and its initial phase number is |
338 |
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* the same as that of parent phaser. |
352 |
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} |
353 |
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|
354 |
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/** |
355 |
< |
* Creates a new Phaser with the given parent and numbers of |
355 |
> |
* Creates a new phaser with the given parent and numbers of |
356 |
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* registered unarrived parties. If parent is non-null, this phaser |
357 |
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* is registered with the parent and its initial phase number is |
358 |
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* the same as that of parent phaser. |
379 |
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/** |
380 |
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* Adds a new unarrived party to this phaser. |
381 |
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* |
382 |
< |
* @return the current barrier phase number upon registration |
382 |
> |
* @return the arrival phase number to which this registration applied |
383 |
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* @throws IllegalStateException if attempting to register more |
384 |
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* than the maximum supported number of parties |
385 |
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*/ |
391 |
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* Adds the given number of new unarrived parties to this phaser. |
392 |
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* |
393 |
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* @param parties the number of parties required to trip barrier |
394 |
< |
* @return the current barrier phase number upon registration |
394 |
> |
* @return the arrival phase number to which this registration applied |
395 |
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* @throws IllegalStateException if attempting to register more |
396 |
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* than the maximum supported number of parties |
397 |
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*/ |
428 |
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* Arrives at the barrier, but does not wait for others. (You can |
429 |
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* in turn wait for others via {@link #awaitAdvance}). |
430 |
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* |
431 |
< |
* @return the barrier phase number upon entry to this method, or a |
422 |
< |
* negative value if terminated |
431 |
> |
* @return the arrival phase number, or a negative value if terminated |
432 |
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* @throws IllegalStateException if not terminated and the number |
433 |
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* of unarrived parties would become negative |
434 |
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*/ |
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if (par == null) { // directly trip |
451 |
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if (casState |
452 |
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(s, |
453 |
< |
trippedStateFor(onAdvance(phase, parties)? -1 : |
453 |
> |
trippedStateFor(onAdvance(phase, parties) ? -1 : |
454 |
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((phase + 1) & phaseMask), parties))) { |
455 |
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releaseWaiters(phase); |
456 |
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break; |
473 |
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} |
474 |
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|
475 |
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/** |
476 |
< |
* Arrives at the barrier, and deregisters from it, without |
477 |
< |
* waiting for others. Deregistration reduces number of parties |
476 |
> |
* Arrives at the barrier and deregisters from it without waiting |
477 |
> |
* for others. Deregistration reduces the number of parties |
478 |
|
* required to trip the barrier in future phases. If this phaser |
479 |
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* has a parent, and deregistration causes this phaser to have |
480 |
< |
* zero parties, this phaser is also deregistered from its parent. |
480 |
> |
* zero parties, this phaser also arrives at and is deregistered |
481 |
> |
* from its parent. |
482 |
|
* |
483 |
< |
* @return the current barrier phase number upon entry to |
474 |
< |
* this method, or a negative value if terminated |
483 |
> |
* @return the arrival phase number, or a negative value if terminated |
484 |
|
* @throws IllegalStateException if not terminated and the number |
485 |
|
* of registered or unarrived parties would become negative |
486 |
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*/ |
511 |
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if (unarrived == 0) { |
512 |
|
if (casState |
513 |
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(s, |
514 |
< |
trippedStateFor(onAdvance(phase, parties)? -1 : |
514 |
> |
trippedStateFor(onAdvance(phase, parties) ? -1 : |
515 |
|
((phase + 1) & phaseMask), parties))) { |
516 |
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releaseWaiters(phase); |
517 |
|
break; |
530 |
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|
531 |
|
/** |
532 |
|
* Arrives at the barrier and awaits others. Equivalent in effect |
533 |
< |
* to {@code awaitAdvance(arrive())}. If you instead need to |
534 |
< |
* await with interruption of timeout, and/or deregister upon |
535 |
< |
* arrival, you can arrange them using analogous constructions. |
533 |
> |
* to {@code awaitAdvance(arrive())}. If you need to await with |
534 |
> |
* interruption or timeout, you can arrange this with an analogous |
535 |
> |
* construction using one of the other forms of the awaitAdvance |
536 |
> |
* method. If instead you need to deregister upon arrival use |
537 |
> |
* {@code arriveAndDeregister}. |
538 |
|
* |
539 |
< |
* @return the phase on entry to this method |
539 |
> |
* @return the arrival phase number, or a negative number if terminated |
540 |
|
* @throws IllegalStateException if not terminated and the number |
541 |
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* of unarrived parties would become negative |
542 |
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*/ |
545 |
|
} |
546 |
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|
547 |
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/** |
548 |
< |
* Awaits the phase of the barrier to advance from the given |
549 |
< |
* value, or returns immediately if argument is negative or this |
550 |
< |
* barrier is terminated. |
551 |
< |
* |
552 |
< |
* @param phase the phase on entry to this method |
553 |
< |
* @return the phase on exit from this method |
548 |
> |
* Awaits the phase of the barrier to advance from the given phase |
549 |
> |
* value, returning immediately if the current phase of the |
550 |
> |
* barrier is not equal to the given phase value or this barrier |
551 |
> |
* is terminated. |
552 |
> |
* |
553 |
> |
* @param phase an arrival phase number, or negative value if |
554 |
> |
* terminated; this argument is normally the value returned by a |
555 |
> |
* previous call to {@code arrive} or its variants |
556 |
> |
* @return the next arrival phase number, or a negative value |
557 |
> |
* if terminated or argument is negative |
558 |
|
*/ |
559 |
|
public int awaitAdvance(int phase) { |
560 |
|
if (phase < 0) |
570 |
|
} |
571 |
|
|
572 |
|
/** |
573 |
< |
* Awaits the phase of the barrier to advance from the given |
574 |
< |
* value, or returns immediately if argument is negative or this |
575 |
< |
* barrier is terminated, or throws InterruptedException if |
576 |
< |
* interrupted while waiting. |
577 |
< |
* |
578 |
< |
* @param phase the phase on entry to this method |
579 |
< |
* @return the phase on exit from this method |
573 |
> |
* Awaits the phase of the barrier to advance from the given phase |
574 |
> |
* value, throwing {@code InterruptedException} if interrupted while |
575 |
> |
* waiting, or returning immediately if the current phase of the |
576 |
> |
* barrier is not equal to the given phase value or this barrier |
577 |
> |
* is terminated. |
578 |
> |
* |
579 |
> |
* @param phase an arrival phase number, or negative value if |
580 |
> |
* terminated; this argument is normally the value returned by a |
581 |
> |
* previous call to {@code arrive} or its variants |
582 |
> |
* @return the next arrival phase number, or a negative value |
583 |
> |
* if terminated or argument is negative |
584 |
|
* @throws InterruptedException if thread interrupted while waiting |
585 |
|
*/ |
586 |
|
public int awaitAdvanceInterruptibly(int phase) |
597 |
|
} |
598 |
|
|
599 |
|
/** |
600 |
< |
* Awaits the phase of the barrier to advance from the given value |
601 |
< |
* or the given timeout elapses, or returns immediately if |
602 |
< |
* argument is negative or this barrier is terminated. |
603 |
< |
* |
604 |
< |
* @param phase the phase on entry to this method |
605 |
< |
* @return the phase on exit from this method |
600 |
> |
* Awaits the phase of the barrier to advance from the given phase |
601 |
> |
* value or the given timeout to elapse, throwing |
602 |
> |
* {@code InterruptedException} if interrupted while waiting, or |
603 |
> |
* returning immediately if the current phase of the barrier is not |
604 |
> |
* equal to the given phase value or this barrier is terminated. |
605 |
> |
* |
606 |
> |
* @param phase an arrival phase number, or negative value if |
607 |
> |
* terminated; this argument is normally the value returned by a |
608 |
> |
* previous call to {@code arrive} or its variants |
609 |
> |
* @param timeout how long to wait before giving up, in units of |
610 |
> |
* {@code unit} |
611 |
> |
* @param unit a {@code TimeUnit} determining how to interpret the |
612 |
> |
* {@code timeout} parameter |
613 |
> |
* @return the next arrival phase number, or a negative value |
614 |
> |
* if terminated or argument is negative |
615 |
|
* @throws InterruptedException if thread interrupted while waiting |
616 |
|
* @throws TimeoutException if timed out while waiting |
617 |
|
*/ |
618 |
< |
public int awaitAdvanceInterruptibly(int phase, long timeout, TimeUnit unit) |
618 |
> |
public int awaitAdvanceInterruptibly(int phase, |
619 |
> |
long timeout, TimeUnit unit) |
620 |
|
throws InterruptedException, TimeoutException { |
621 |
|
if (phase < 0) |
622 |
|
return phase; |
665 |
|
} |
666 |
|
|
667 |
|
/** |
639 |
– |
* Returns {@code true} if the current phase number equals the given phase. |
640 |
– |
* |
641 |
– |
* @param phase the phase |
642 |
– |
* @return {@code true} if the current phase number equals the given phase |
643 |
– |
*/ |
644 |
– |
public final boolean hasPhase(int phase) { |
645 |
– |
return phaseOf(getReconciledState()) == phase; |
646 |
– |
} |
647 |
– |
|
648 |
– |
/** |
668 |
|
* Returns the number of parties registered at this barrier. |
669 |
|
* |
670 |
|
* @return the number of parties |
674 |
|
} |
675 |
|
|
676 |
|
/** |
677 |
< |
* Returns the number of parties that have arrived at the current |
678 |
< |
* phase of this barrier. |
677 |
> |
* Returns the number of registered parties that have arrived at |
678 |
> |
* the current phase of this barrier. |
679 |
|
* |
680 |
|
* @return the number of arrived parties |
681 |
|
*/ |
694 |
|
} |
695 |
|
|
696 |
|
/** |
697 |
< |
* Returns the parent of this phaser, or null if none. |
697 |
> |
* Returns the parent of this phaser, or {@code null} if none. |
698 |
|
* |
699 |
< |
* @return the parent of this phaser, or null if none |
699 |
> |
* @return the parent of this phaser, or {@code null} if none |
700 |
|
*/ |
701 |
|
public Phaser getParent() { |
702 |
|
return parent; |
725 |
|
* Overridable method to perform an action upon phase advance, and |
726 |
|
* to control termination. This method is invoked whenever the |
727 |
|
* barrier is tripped (and thus all other waiting parties are |
728 |
< |
* dormant). If it returns true, then, rather than advance the |
729 |
< |
* phase number, this barrier will be set to a final termination |
730 |
< |
* state, and subsequent calls to {@code isTerminated} will |
731 |
< |
* return true. |
728 |
> |
* dormant). If it returns {@code true}, then, rather than advance |
729 |
> |
* the phase number, this barrier will be set to a final |
730 |
> |
* termination state, and subsequent calls to {@link #isTerminated} |
731 |
> |
* will return true. |
732 |
|
* |
733 |
< |
* <p> The default version returns true when the number of |
733 |
> |
* <p>The default version returns {@code true} when the number of |
734 |
|
* registered parties is zero. Normally, overrides that arrange |
735 |
|
* termination for other reasons should also preserve this |
736 |
|
* property. |
737 |
|
* |
738 |
< |
* <p> You may override this method to perform an action with side |
738 |
> |
* <p>You may override this method to perform an action with side |
739 |
|
* effects visible to participating tasks, but it is in general |
740 |
|
* only sensible to do so in designs where all parties register |
741 |
< |
* before any arrive, and all {@code awaitAdvance} at each phase. |
742 |
< |
* Otherwise, you cannot ensure lack of interference. In |
743 |
< |
* particular, this method may be invoked more than once per |
725 |
< |
* transition if other parties successfully register while the |
726 |
< |
* invocation of this method is in progress, thus postponing the |
727 |
< |
* transition until those parties also arrive, re-triggering this |
728 |
< |
* method. |
741 |
> |
* before any arrive, and all {@link #awaitAdvance} at each phase. |
742 |
> |
* Otherwise, you cannot ensure lack of interference from other |
743 |
> |
* parties during the invocation of this method. |
744 |
|
* |
745 |
|
* @param phase the phase number on entering the barrier |
746 |
|
* @param registeredParties the current number of registered parties |
945 |
|
return p; |
946 |
|
} |
947 |
|
|
948 |
< |
// Temporary Unsafe mechanics for preliminary release |
934 |
< |
private static Unsafe getUnsafe() throws Throwable { |
935 |
< |
try { |
936 |
< |
return Unsafe.getUnsafe(); |
937 |
< |
} catch (SecurityException se) { |
938 |
< |
try { |
939 |
< |
return java.security.AccessController.doPrivileged |
940 |
< |
(new java.security.PrivilegedExceptionAction<Unsafe>() { |
941 |
< |
public Unsafe run() throws Exception { |
942 |
< |
return getUnsafePrivileged(); |
943 |
< |
}}); |
944 |
< |
} catch (java.security.PrivilegedActionException e) { |
945 |
< |
throw e.getCause(); |
946 |
< |
} |
947 |
< |
} |
948 |
< |
} |
948 |
> |
// Unsafe mechanics |
949 |
|
|
950 |
< |
private static Unsafe getUnsafePrivileged() |
951 |
< |
throws NoSuchFieldException, IllegalAccessException { |
952 |
< |
Field f = Unsafe.class.getDeclaredField("theUnsafe"); |
953 |
< |
f.setAccessible(true); |
954 |
< |
return (Unsafe) f.get(null); |
955 |
< |
} |
950 |
> |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
951 |
> |
private static final long stateOffset = |
952 |
> |
objectFieldOffset("state", Phaser.class); |
953 |
|
|
954 |
< |
private static long fieldOffset(String fieldName) |
955 |
< |
throws NoSuchFieldException { |
959 |
< |
return UNSAFE.objectFieldOffset |
960 |
< |
(Phaser.class.getDeclaredField(fieldName)); |
954 |
> |
private final boolean casState(long cmp, long val) { |
955 |
> |
return UNSAFE.compareAndSwapLong(this, stateOffset, cmp, val); |
956 |
|
} |
957 |
|
|
958 |
< |
static final Unsafe UNSAFE; |
964 |
< |
static final long stateOffset; |
965 |
< |
|
966 |
< |
static { |
958 |
> |
private static long objectFieldOffset(String field, Class<?> klazz) { |
959 |
|
try { |
960 |
< |
UNSAFE = getUnsafe(); |
961 |
< |
stateOffset = fieldOffset("state"); |
962 |
< |
} catch (Throwable e) { |
963 |
< |
throw new RuntimeException("Could not initialize intrinsics", e); |
960 |
> |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field)); |
961 |
> |
} catch (NoSuchFieldException e) { |
962 |
> |
// Convert Exception to corresponding Error |
963 |
> |
NoSuchFieldError error = new NoSuchFieldError(field); |
964 |
> |
error.initCause(e); |
965 |
> |
throw error; |
966 |
|
} |
967 |
|
} |
968 |
|
|
969 |
< |
final boolean casState(long cmp, long val) { |
970 |
< |
return UNSAFE.compareAndSwapLong(this, stateOffset, cmp, val); |
969 |
> |
/** |
970 |
> |
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
971 |
> |
* Replace with a simple call to Unsafe.getUnsafe when integrating |
972 |
> |
* into a jdk. |
973 |
> |
* |
974 |
> |
* @return a sun.misc.Unsafe |
975 |
> |
*/ |
976 |
> |
private static sun.misc.Unsafe getUnsafe() { |
977 |
> |
try { |
978 |
> |
return sun.misc.Unsafe.getUnsafe(); |
979 |
> |
} catch (SecurityException se) { |
980 |
> |
try { |
981 |
> |
return java.security.AccessController.doPrivileged |
982 |
> |
(new java.security |
983 |
> |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
984 |
> |
public sun.misc.Unsafe run() throws Exception { |
985 |
> |
java.lang.reflect.Field f = sun.misc |
986 |
> |
.Unsafe.class.getDeclaredField("theUnsafe"); |
987 |
> |
f.setAccessible(true); |
988 |
> |
return (sun.misc.Unsafe) f.get(null); |
989 |
> |
}}); |
990 |
> |
} catch (java.security.PrivilegedActionException e) { |
991 |
> |
throw new RuntimeException("Could not initialize intrinsics", |
992 |
> |
e.getCause()); |
993 |
> |
} |
994 |
> |
} |
995 |
|
} |
996 |
|
} |